continuant vs unaltering

continuant

adj

  • Continuing; prolonged; sustained. 

noun

  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

unaltering

adj

  • Not altering; unchanging, constant. 

How often have the words continuant and unaltering occurred in a corpus of books? (source: Google Ngram Viewer )